Problem: The grades on a physics midterm at Oak are normally distributed with $\mu = 73$ and $\sigma = 3.0$. Ishaan earned a $74$ on the exam. Find the z-score for Ishaan's exam grade. Round to two decimal places.
Explanation: A z-score is defined as the number of standard deviations a specific point is away from the mean We can calculate the z-score for Ishaan's exam grade by subtracting the mean $(\mu)$ from his grade and then dividing by the standard deviation $(\sigma)$ $ { z = \dfrac{x - {\mu}}{{\sigma}}} $ $ { z = \dfrac{74 - {73}}{{3.0}}} $ ${ z \approx 0.33}$ The z-score is $0.33$. In other words, Ishaan's score was $0.33$ standard deviations above the mean.